In　order　to　explore　the　effect　of　the　silver　content　of　lead-free　solder　joints　on　the　reliability　in　the　drop　condition,　the　drop　tests　were　carried　out　with　three　different　kinds　of　materials　(Sn-3.0Ag-0.5Cu,　Sn-1.0Ag-0.5Cu　and　Sn-0.3Ag-0.7Cu).　The　half　sine　input　acceleration　pulse　was　measured　at　the　corner　of　the　drop　block,　G　levels　and　pulse　duration　are　1500　Gs　and　0.5　millisecond.　Using　electrical　test,　optical　microscope,　scanning　electron　microscope　and　other　means,　the　failure　position　of　solder　joint　had　be　identified.　Failed　BGA　solder　joints　were　cross-sectioned　and　metallurgical　analysis　to　investigate　failure　mechanisms　of　BGA　lead-free　solder　joints　under　impact　loading.　The　results　showed　that　most　of　the　failures　locate　in　the　PCB　side　for　the　three　kinds　of　different　joining　materials,　The　most　periphery　solder　joints　are　most　likely　to　failure,　and　the　thickness　of　IMCS　gradually　decrease　and　the　life　of　solder　joint　gradually　enhance　with　the　content　of　Ag　reducing.